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PuTTY TCP User Guide

Paul Nong-Laolam edited this page Jun 3, 2026 · 7 revisions

This guide provides instructions for installing, configuring, and using PuTTY to communicate with and control ESPEC chambers equipped with GL, P300, SCP220, ES102 controllers, and Watlow F4T controller via TCP/IP interface. PuTTY is a free and open-source terminal emulator and remote access client. While PuTTY is most commonly used on MS Windows to access Linux and UNIX systems via SSH (Secure Shell), in this guide, we will illustrate how to use it to connect to a controller device over a network.

1 Download and Install PuTTY

The following procedure outlines the steps to download and install PuTTY on your MS Windows PC or execute it from the download folder. If the software is intended to be used regularly, then the install one would be recommended.

Procedure:

  1. Open a web browser.

  2. Go to the PuTTY official webpage:

    https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

  3. Download the MSI (Window Installer) file (64-bit x86). Note: It should also be available from the Microsoft Store.

  4. To install:

    • In the Downloads folder, double-click the installer (e.g., putty-64bit-[version]-installer.msi)

    • Follow the installation prompts.

    • Accept the default installation settings unless changes are required; add shortcut to PuTTY on the Desktop.

    • Click Install, then click finish when ths installation is done.

2 Prepare Device for PuTTY Communication

The following table summarizes the communication options available for using PuTTY with different controller types.

Controller Communication Interface and Operation
GL TCP/IP communication interface is available by default
P300 1. TCP/IP communication through ESPEC Web Controller port forwarding. 2. TCP/IP communication using an Ethernet-to-RS232 serial adapter (not covered in this document).
SCP220 TCP/IP communication through ESPEC Web Controller port forwarding
ES102 TCP/IP communication through ESPEC Web Controller port forwarding
Watlow F4T 1. TCP/IP communication through ESPEC Web Controller port forwarding. 2. Direct TCP/IP communication via native communication interface through port 5025 using SCPI command protocol

2.1 GL

By default, the GL controller system uses TCP/IP to establish remote communication. Refer to the GL Communications Manual for details on how to obtain the IP address.

Refer to the ESPEC GL Controller User's Manual on how to enable the remote communication via TCP/IP.

2.2 P300, SCP220, ES102 and Watlow F4T

Complete the following steps to set ESPEC Web Controller (EWC) to allow TCP/IP port forwarding.

Procedure:

  1. Log in as admin (or into an account with admin privileges)

  2. Click Settings in the menu bar, followed by the API Settings submenu

  3. Click to select No Authentication from the list in the Authentication Mode field (see arrow)

  4. Check the box under the Direct Controller Acccess (see arrow). Note: The default TCP port for the GL, P300, SCP220, and ES102 is 10001. The Watlow F4T uses TCP port 502 by default for Modbus TCP communications. The following figures depict a TCP port frowarding configuration for P300, SCP220 or ES102 which shows port 10001 and F4T with prot 502, respectively.

    EWC TCP port forwarding configuration

    EWC TCP port forwarding configuration

  5. Click the Save icon in the upper-right corner (see arrow)

  6. Click Server Settings (2nd submenu from the bottom)

  7. Click the Power button icon (upper-right corner), and click Yes to reboot EWC

  8. Proceed to Section 3 to launch PuTTY.

2.3 F4T through port 5025 via SCPI Commands

Watlow has implemented ASCII plain-text SCPI (short for Standard Commands for Programamble Instruments) commands sent over TCP/IP to communicate with their F4T models via Modbus TCP with default TCP port 5025. SCPI commands are sent over a raw TCP socket. A client opens a TCP socket connection and sends ASCII commands terminated by a line feed (\n) to the F4T.

This process can be achieved by connecting the F4T to the main network using DHCP or static IP configuration. The F4T IP address can be found in the Network Settings on the Ethernet page. To establish communication with the F4T using PuTTY, configure the connection with the controller's IP address, TCP port 5025, and RAW connection type. The F4T must have Firmware Revision 03:06:0011 or higher (release in May 5, 2017 and later).

Once the F4T IP address is known, proceed to the next section to launch PuTTY.

3 Launch PuTTY and Configure Communication Protocol

IP address of the device, port number and the communication type are three important components required to establish communication through PuTTY.

Procedure:

  1. Launch PuTTY. Its Configuration page depicted as follows:

    PuTTY configuration interface and settings

  2. Enter IP address (or hostname) in the field indicated by Callout 1

  3. Set 10001 in the Port field (see Callout 2) for GL, P300, SCP220 and ES102. For Watlow F4T via EWC port forwarder, use 502. For a direct SCPI communication with F4T, use port 5025.

  4. Select connection type to RAW (see Callout 3)

  5. Click Open to start the session (see Callout 4)

4 Issue Commands on PuTTY

The following figure displays the PuTTY terminal, showing the IP address of the device it is communicating with.

GL command-response terminal on PuTTY

Each command is issued with the line feed (Enter key). A response from the controller is displayed following each command. The read command is issued with a question mark (?). The set command is issued with out it.

P300 command-response terminal on PuTTY

F4T command-response terminal on PuTTY via SCPI communication

Refer to the GL, P300, SCP220 or ES102 Communications Manual for details on interpreting the chamber's response and how to issue other commands. For F4T, refer to the manufacturer's manual.

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