Configuring analog outputs - DMT152

DMT152 User Guide
Document code
M210865EN
Revision
K
Language
English
Product
DMT152
Document type
User guide
DMT152 has two analog output channels. These channels can function either as normal measurement channels, or produce an ON/OFF output if the measurement exceeds a given alarm level (limit alarm) or if the measurement reading is frozen (for example, during sensor purge).
  • In the normal operation mode, a channel outputs voltage or current that corresponds to the reading of the selected measurement parameter.
  • In the ON/OFF output mode, a channel outputs a specified voltage or current level. This mode is used by the limit alarm and the purge status alarm.
  • In the LED alarm output mode, the channel outputs operation voltage for the LED cable. The LED will light up to indicate a frozen measurement output which is typically caused by transmitter start-up or sensor purge. The LED will blink at approximately 0.5 Hz if the malfunction alarm is active. The LED will not light up for the limit alarm.

Additionally, DMT152 has a malfunction alarm that is always enabled in normal operation mode. The malfunction alarm can also be enabled for a channel in ON/OFF output mode. See Malfunction alarm.

When the transmitter is ordered from Vaisala, the modes are configured as specified in the order form. You can change the operation settings after delivery using the AMODE command:

Table 1. AMODE command
Syntax Description
AMODE [c1 c2]<cr>
c1 = Channel 1 analog output mode. Available options are:
1
0 … 20 mA
2
4 … 20 mA
4
0 … 5 V
5
0 … 10 V
7
I alarm (ON/OFF output using current)
8
U alarm (ON/OFF output using voltage)

Modes 1 … 5 are normal measurement modes, where malfunction alarm is always enabled, and limit alarm and purge status alarm are disabled.

c2 = Channel 2 analog output mode. Available options are:
1
0 … 20 mA
2
4 … 20 mA
4
0 … 5 V
5
0 … 10 V
6
LED alarm
7
I alarm (ON/OFF output using current)
8
U alarm (ON/OFF output using voltage)

Enable mode 6 for channel 2 if you are using the Vaisala LED cable.

Example:

amode 2 1
Ch1 output     : 4 ... 20 mA
Ch2 output     : 0 ... 20 mA