Copyright and cleanup.

README.md

@@ -11,6 +11,11 @@ This implementation uses `ffi` to export wrapper functions.
 # TODO
 
 1. Error handling - provide an interface for a custom error handler
-2. Solve the FFI DynamicLibrary issue (it appends the .dylib library suffix which breaks macOS)
+2. Solve the FFI DynamicLibrary issue (it appends the .dylib library suffix which breaks on recent macOS)
 3. Make it more "npm package-y"
 4. Implement the full v19 API (and constants!)
+
+
+# Thanks
+
+Originally inspired by Jürgen Skrotzky's [visa32 project](https://github.com/Jorgen-VikingGod/visa32).

n6705b.js

@@ -1,22 +1,26 @@
 /**
- * EEMBC implementation of N6705B control for IoTConnect frameworks.
+ * Copyright (C) Peter Torelli
  *
- * Copyright (c) EEMBC
- *
- * Original author: P.Torelli (based on Python code by S.Allen/Dialog)
+ * Licensed under Apache 2.0
+ * 
+ * Interface implementation for Keysight N6705B
  */
 
 /**
+ * TODO List:
+ *
  * TODO: How do we turn off the emon after sampling automatically?
  * TODO: Should there be checks to prevent triggering if init() hasn't been
  *       called? (e.g., this.ready)
+ * TODO: SCPI error-handling is dodgy: rather than send a RESP, I have to check
+ *       the panel of the Keysight for an error. Really?
  */
 
 const
 	visa = require('./ni-visa.js'),
 	vcon = require('./ni-visa-constants.js'),
 	pause = require('./pause.js'),
-	debug = require('debug')('n6705b'),
+	debug = require('debug')('emon'),
 	util = require('util')
 
 const MIN_PERIOD_S = 20e-6;
@@ -152,17 +156,13 @@ KeysightN6705B.prototype.setup_p = async function (voltageV=3.0, rateHz=1000) {
  */
 KeysightN6705B.prototype.timeAcquire_p = async function (timeS=10) {
 	debug('timeAcquire_p');
-	// TODO this needs to be EXTernal for the BNC backpanel input
+	// TODO This needs to be EXTernal for the BNC backpanel input
 	visa.viWrite(this.inst, 'TRIG:DLOG:SOUR BUS');
 	visa.viWrite(this.inst, `SENS:DLOG:TIME ${timeS}`);
 	resp = visa.vhQuery(this.inst, 'SENS:DLOG:TIME?')
 	let actualTimeS = parseFloat(resp);
-	// TODO: Recommended by Steve Allen
-	await pause(0.5);
-	// TODO: How do we tell if we run out of disk space?
+	// TODO How do we tell if we run out of disk space?
 	visa.viWrite(this.inst, 'INIT:DLOG "internal:\\data1.dlog"')
-	// TODO: Recommended by Steve Allen
-	await pause(0.5);
 	return actualTimeS;
 }
 
@@ -173,36 +173,42 @@ KeysightN6705B.prototype.selfTrigger = function () {
 KeysightN6705B.prototype.downloadData = function () {
 	debug('downloadData');
 	let resp;
+	let status;
 	this.off();
 	resp = visa.vhQuery(this.inst, 'MMEM:ATTR? "internal:\\data1.dlog", "FileSize"');
 	// TODO: Odd, why suddenly are there quotes in the response?
 	resp = resp.replace(/"/g, '');
 	let bytes = parseInt(resp);
 	debug(`File ${DEFAULT_LOG_FILE} size is ${bytes} bytes`);
 	let buffer = Buffer.alloc(0);
-	visa.viWrite(this.inst, `MMEM:DATA? "${DEFAULT_LOG_FILE}"`)
-	let status;
+	visa.viWrite(this.inst, `MMEM:DATA:DEF? "${DEFAULT_LOG_FILE}"`)
 	// TODO: Load the ENTIRE file into memory could be a bad idea in the future
-	let check = 0;
+	const start = process.hrtime();
 	do {
-		[status, resp] = visa.viReadRaw(this.inst);
-		console.log(resp.toString());
-		console.log(status.toString(16), resp.length);
-		check += resp.length;
+		[status, resp] = visa.viReadRaw(this.inst, 512);
 		buffer = Buffer.concat([buffer, resp], buffer.length + resp.length)
+		if (status & vcon.VI_ERROR) {
+			throw new Error("Error reading dlog file", status.toString(16));
+		}
 	} while (status && !(status & vcon.VI_ERROR));
-	console.log('status      ', status)
-	console.log('buffer sum  ', check);
+	const diff = process.hrtime(start);
+	const sec = diff[1] / 1e9 + diff[0];
+	const tpt = (buffer.length / 1024) / sec;
+	debug('bytes read  ', buffer.length);
+	debug('FileSize?   ', bytes);
+	debug('speed       ', tpt.toPrecision(3), 'KB/s');
 	// Fast-forward past the header
-	let startRaw = buffer.indexOf('</dlog>\n') + '</dlog>\n'.length;
-	if (startRaw === 0) {
+	let offset = buffer.indexOf('</dlog>\n') + '</dlog>\n'.length;
+	if (offset === 0) {
 		throw new Error('Failed to find start of binary data');
 	}
 	// The 8 bytes after the header are also not needed
-	console.log('first dword ', buffer.readUInt32BE(startRaw));
-	console.log('scnd dword  ', buffer.readUInt32BE(startRaw + 4));
-	console.log("Skip bytes = ", startRaw + 8);
-	return buffer.slice(startRaw + 8, bytes);
+	debug('1st dword   ', buffer.readUInt32BE(offset).toString(16));
+	debug('2nd dword   ', buffer.readUInt32BE(offset + 4).toString(16));
+	offset += 8;
+	debug('Offset      ', offset, 'B');
+	// BUGBUG: Often more bytes are sent back than there are in the file, why?
+	return buffer.slice(offset,  buffer.length);
 }
 
 KeysightN6705B.prototype.off = function () {

ni-visa-constants.js

@@ -1,4 +1,10 @@
-// Constants for the VISA Library 5.8 Specification
+/**
+ * Copyright (C) Peter Torelli
+ *
+ * Licensed under Apache 2.0
+ * 
+ * Constants for the VISA Library 5.8 Specification by National Instruments
+ */
 
 const constants = {
 
@@ -648,9 +654,10 @@ const constants = {
  * 0xBFFF000E = 0x80000000 + 0x3FFF000E = VI_ERROR_INV_OBJECT
  *            = 3221159950
  *            = -1073807346
+ * Returns text string or null
  */
 function decodeStatus (code) {
-	let key;
+	let key = null;
 	Object.keys(constants).some((x, y) => {
 		if (x.match(/^VI_(SUCCESS|WARN|ERROR)/)) {
 			if (code == constants[x]) {

ni-visa.js

@@ -1,11 +1,16 @@
-/*
-
-TODO:
-
-- Error handling. How we gonna do this? Return a status or just throw?
-- debug()
+/**
+ * Copyright (C) Peter Torelli
+ *
+ * Licensed under Apache 2.0
+ * 
+ * Interface wrapper to the VISA dynamic library.
+ */
 
-*/
+/**
+ * TODO List
+ *
+ * TODO: Error handling. Throw? Return status? How should we do this?
+ */
 
 const
 	debug = require('debug')('ni-visa'),
@@ -68,18 +73,28 @@ const libVisa = ffi.Library(dllName, {
 	'viWrite': [ViStatus, [ViSession, 'string', ViUInt32, ViPUInt32]],
 });
 
-function errorHandler (status) {
+// TODO: since error handling is undecided, every function calls this
+function statusCheck (status) {
 	if (status & vcon.VI_ERROR) {
 		console.log('Warning: VISA Error: 0x' + (status >>> 0).toString(16).toUpperCase());
 		throw new Error();
+	} else {
+		if (status) {
+			let str = vcon.decodeStatus(status);
+			if (str != null) {
+				debug(`non-error status check: ${status.toString(16)} ${str}`);
+			} else {
+				debug(`non-error status check: ${status.toString(16)}`);
+			}
+		}
 	}
 }
 
 function viOpenDefaultRM () {
 	let status;
 	let pSesn = ref.alloc(ViSession);
 	status = libVisa.viOpenDefaultRM(pSesn);
-	errorHandler(status);
+	statusCheck(status);
 	return [status, pSesn.deref()];
 }
 
@@ -89,7 +104,7 @@ function viFindRsrc (sesn, expr) {
 	let pRetcnt = ref.alloc(ViUInt32);
 	let instrDesc = Buffer.alloc(512);
 	status = libVisa.viFindRsrc(sesn, expr, pFindList, pRetcnt, instrDesc);
-	errorHandler(status);
+	statusCheck(status);
 	return [
 		status,
 		pFindList.deref(),
@@ -103,7 +118,7 @@ function viFindNext (findList) {
 	let status;
 	let instrDesc = Buffer.alloc(512);
 	status = libVisa.viFindNext(findList, instrDesc);
-	errorHandler(status);
+	statusCheck(status);
 	return [
 		status,
 		// Fake null-term string
@@ -115,46 +130,48 @@ function viOpen (sesn, rsrcName, accessMode=0, openTimeout=2000) {
 	let status;
 	let pVi = ref.alloc(ViSession);
 	status = libVisa.viOpen(sesn, rsrcName, accessMode, openTimeout, pVi);
-	errorHandler(status);
+	statusCheck(status);
 	return [status, pVi.deref()];
 }
 
 function viClose (vi) {
 	let status;
 	status = libVisa.viClose(vi);
-	errorHandler(status);
+	statusCheck(status);
 	return status;
 }
 
 // TODO ... assuming viRead always returns a string, probably wrong
 function viRead (vi, count=512) {
-	debug(`read (${count})`);
 	let status;
 	let buf = Buffer.alloc(count);
 	let pRetCount = ref.alloc(ViUInt32);
 	status = libVisa.viRead(vi, buf, buf.length, pRetCount)
-	errorHandler(status);
+	statusCheck(status);
+	debug(`read (${count}) -> ${pRetCount.deref()}`);
 	return [status, ref.reinterpret(buf, pRetCount.deref(), 0).toString()];
 }
 
-// Returns the raw Buffer object
+// Returns the raw Buffer object rather than a decoded string
 function viReadRaw (vi, count=512) {
-	debug(`read (${count})`);
 	let status;
 	let buf = Buffer.alloc(count);
 	let pRetCount = ref.alloc(ViUInt32);
 	status = libVisa.viRead(vi, buf, buf.length, pRetCount)
-	errorHandler(status);
-	return [status, buf];
+	statusCheck(status);
+	debug(`readRaw: (${count}) -> ${pRetCount.deref()}`);
+	return [status, buf.slice(0, pRetCount.deref())];
 }
 
 function viWrite (vi, buf) {
 	debug('write:', buf);
 	let status;
 	let pRetCount = ref.alloc(ViUInt32);
 	status = libVisa.viWrite(vi, buf, buf.length, pRetCount)
-	debug('write:status:', status);
-	errorHandler(status);
+	statusCheck(status);
+	if (pRetCount.deref() != buf.length) {
+		throw new Error('viWrite length fail')
+	}
 	return [status, pRetCount.deref()];
 }
 
@@ -185,6 +202,7 @@ function vhListResources (sesn, expr='?*') {
  */
 function vhQuery (vi, query) {
 	viWrite(vi, query);
+	// TODO: return status as well?
 	return viRead(vi)[1];
 }
 

test.js

@@ -1,31 +1,41 @@
-let
+/**
+ * Copyright (C) Peter Torelli
+ *
+ * Licensed under Apache 2.0
+ * 
+ * Just a test area.
+ */
+
+ let
 	visa = require('./ni-visa.js'),
 	vcon = require('./ni-visa-constants.js'),
 	n6705b = require('./n6705b.js'),
 	pause = require('./pause.js')
 
-let sampleTime = 10;
+let sampleTime = 6;
 async function main_p () {
 	try {
 		let ks = new n6705b();
 		ks.init();
 		[actualVolts, actualPeriodS] = await ks.setup_p(3.0, 1/20e-6);
 		actualTimeS = await ks.timeAcquire_p(sampleTime);
 		ks.selfTrigger();
-		await pause(actualTimeS + 1);
+		await pause(11);
 		ks.off();
+		await pause(1);
 		let data = ks.downloadData();
 		console.log('Total bytes sampled', data.length);
 		console.log('Total samples', data.length / 4);
 		ks.close();
 		console.log(`Voltage ${actualVolts} V, Period ${actualPeriodS * 1e6} usec.`);
 		let energy = 0;
-		for (let i=0, j=0; i<data.length; i+=4, j+=actualPeriodS) {
-			console.log(j, data.readFloatBE(i));
+		// why always 1 byte off
+		for (let i=0, j=0; i<data.length-4; i+=4, j+=actualPeriodS) {
+			//console.log(i, j, data.readFloatBE(i));
 			energy += (actualVolts * data.readFloatBE(i)) * actualPeriodS;
 		}
 		console.log(data.length);
-		console.log(energy, data.length / 4 * actualPeriodS);
+		console.log((energy * 1e6).toPrecision(3), (data.length / 4 * actualPeriodS).toPrecision(3));
 	} catch (error) {
 		console.error(error.stack);
 	}