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Troubleshooting
7.25 Troubleshooting
7.25.1 What are some basic guidelines when installing a CLSS Gateway?
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Polling should be done slowly to start.
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Use Modscan ® to debug the system rather than a more complicated client. Verify that
registers are being updated as events happen on the NFN network/panel.
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Make sure gateway can be pinged from the same computer on which the client
application is being installed.
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Check and double check the power supplies as well as all cabling.
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Make sure the client supports Unit IDs.
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Stop the client from sending a subsequent request until after it receives a response
from the gateway.
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Make sure the client accepts all exception responses. Including 0xA and 0xB.
Use Wireshark ® to debug IP traffic.
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Be sure only one client is polling the gateway.
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Check the CLSS Gateway configuration tool and be sure that the Authorized Client IP
address is set to 0.0.0.0. If using the Authorized Client IP security feature, confirm that
the address in the gateway matches the address in the Modbus client.
7.25.2 How fast can the Modbus client poll the gateway?
The polling rate is a function of several variables. Some issues that will determine the
maximum poll rate are:
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The size of the NFN network that is being monitored.
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The number of points on the panels.
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The event activity on the NFN network/panel (i.e. VeriFire downloads).
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Requests for analog values are much slower than other requests
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If only a partial response form the gateway is seen in the Modbus client, try increasing
the "response time out" value in the client to a larger value. If the value is set to 5
seconds or more, this should be adequate. The exact response time out will depend on
IP network delays and routing. On a small IP network, the gateway responds to a read
of 100 register in less than 1 second.
The gateway also has some processing overhead in order to do such things as maintain
the registers.
7.25.3 How can I tell if the gateway is running?
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Ping the gateway from the computer on which the Modbus client is running.
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Use Wireshark to analyze the data on the IP network.
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Modscan was one tool that was used during development to test the gateway. It is
designed primarily as a testing device for verification of correct protocol operation in
new or existing systems.
7.25.4 How do I recover a lost password from the gateway?
If the password for the gateway is lost, programming changes cannot be made. In this
situation, the gateway settings must be reset.
7.25.5 What is an "initialization read" for analog values?
This is the first read of up to 10 analog values from a 4–20 mA module. This first read tells the
gateway that it should begin a polling routine for the analog values in this request. The first
response from the initialization will usually be all zeros. Subsequent responses will have the actual
values.
7.25.6 How many analog values can I read at a time?
Ten analog values can be read at one time. An initialization read must be performed.
7.25.7 Why do I get an exception code when trying to read an analog value?
There are several reasons why an exception code is received when requesting an analog
value:
CLSS Gateway - Installation and Users' Manual | P/N:LS10248-000HW-E | REV. F | FEB/11/2022
Modbus Communications
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Table of Contents
Troubleshooting
