Teledyne 2002 instruction manual Operation, Channel Channel

8.2Operation

The 4-20 mA output option board provides dual channel current output linearly proportional to the HPM 2002’s pressure reading. The first channel corresponds to the higher pressure range (0- 1024 Torr). The second channel corresponds to the lower pressure range (0-1000mTorr). The equations below give the output currents for a given pressure:

I(Channel 1) = 4 mA + (P(Torr))* (	16mA )
	1024 Torr

I(Channel 2) = 4 mA + (P(mTorr))* ( 100016mAmTorr)

Note that for both channels, the output is always between 4mA and 20mA. Specifically, when the pressure is below 1 Torr, channel 1 current will be approaching 4mA. Also, when the pressure is above 1 Torr channel 2 current will be saturated at 20mA.

Channel 1

Channel 2

1

3

8

7

Internal loop power out

Loop in

Internal loop power out

Loop in

Figure 8.2

page 38 Model 2002