Emerson Process Management 1500 manual Performing a loop test, Flowmeter Startup

Flowmeter Startup

WARNING

Upon transmitter startup or abnormal power reset, any external device controlled by a discrete output may be momentarily activated.

Upon transmitter startup or abnormal power reset, discrete output states are unknown. As a result, an external device controlled by a discrete output may receive current for a brief period.

When using Channel B as a discrete output:

•You can prevent current flow upon normal startup by setting Channel B polarity to active low (see Section 4.6).

•There is no programmatic method to prevent current flow for Channel B upon abnormal power reset. You must design the system so that a brief current flow to the external device controlled by Channel B cannot cause negative consequences.

When using Channel C as a discrete output, there is no programmatic method to prevent current flow upon either transmitter startup or abnormal power reset. You must design the system so that a brief current flow to the external device controlled by Channel C cannot cause negative consequences.

3.3Performing a loop test

A loop test is a means to:

•Verify that the mA outupt is being sent by the transmitter and received accurately by the receiving device

•Determine whether or not you need to trim the mA output

•Select and verify the discrete output voltage

•Read the discrete input

Perform a loop test on all inputs and outputs available on your transmitter. Before performing the loop tests, ensure that your transmitter terminals are configured for the input/outputs that will be used in your application (see Section 4.3).

ProLink II is used for loop testing. See Figure 3-1 for the loop test procedure. Note the following:

•The mA reading does not need to be exact. You will correct differences when you trim the mA output. See Section 3.4.

10 Micro Motion® Model 1500 Transmitters with the Filling and Dosing Application