User Guide > How many instruments can be connected to SpecView?

Can SpecView read values from multiple instruments? And if so, how many instruments can SpecView read values from?

Yes, SpecView can read values from multiple instruments, the limits are:

For Serial comms:

The number of controllers that can be connected to SpecView is only limited by the available addresses on the controllers. Most instruments go to 99 addresses (254 for Modbus) and SpecView supports up to 40 COM ports.

RS422 and RS485 would need repeaters if there are more than 16 or 32 instruments respectively. Please see the instrument manufacturer's instructions or the comms converter's manual.

If there are a large number of instruments communicating at a relatively slow rate, then it can take a long time to acquire the data from them all if they are on a single COM port.

By splitting the instruments onto two or more separate comms lines, you can increase the data rate because SpecView will gather data from all ports simultaneously.

However, this would require SpecView’s Multiport option on the license.

For correct correct daisy-chain wiring see Wiring Tips.

For comms over TCP:

There is no practical limit to the number of recorders, but be aware that the performance of the computer will be affected if there are many tags being requested from many recorders at a fast rate.

For both Serial comms and TCP:

You can have a combination of the above and this would also require SpecView’s Multiport option on the license.

Note: For different communications protocols:

If the instruments are not using the same communications protocol then SpecView’s Multiport option will also be required, so that all the instruments that communicate using one protocol are on one port, and instruments that communicate using a different protocol are on another.

It is not possible to mix communications protocols on a single port.