New Era NE-4000 Multi-Phaser Programmable Double Syringe - Manual (Page 46)

New Era Pump Systems Inc.
www.SyringePump.com
Model NE-4000 Multi-Phaser™
Publication #1200-01 41 09/05/14
10. Logic Interface: TTL Input and Output
New Era Pump Systems Inc.
WWW.SYRINGEPUMP.COM
(631) 249-1392
Farmingdale, NY [email protected]
12
1.0
4000
Figure 2: Rear of Pump
On the rear of the pump is a DB-9 connector, below the ‘TTL-I/O’ label, which is used for TTL I/O. The logic
signals on this connector permit bi-directional control with external equipment.
Control input TTL logic levels must be held steady for a minimum of 100 ms to be recognized. To minimize the
possibility of false signals caused by glitches and ringing, which could be caused by the closure of mechanical
switches, TTL control inputs are firmware filtered. With a sampling period of 50 ms, glitches of less than 100 ms
are filtered out.
Edge detection requires the detection of a change in TTL levels. With a minimum of 100 ms to detect a level, an
edge requires a minimum of 200 ms to be detected. Since the next level change can be detected in 100 ms, creating
another edge, the maximum edge to edge frequency is 10 Hz.
Edge changes to the ‘Pumping Direction’ and ‘Operational Trigger’ inputs must occur at least 50 ms apart.
Falling edge refers to a logic high to logic low transition. Rising edge refers to a logic low to a logic high
transition. To guarantee recognition of logic levels, voltages on the input lines must be within the following
ranges:
TTL logic low (0): 0 to 1.5 V
logic high (1): 3.5 to 5.25 V
The Vcc and Ground pins, pins 1 and 9, are for logic reference only. To assure proper voltage levels, the Ground
pin should always be connected to the signal ground of a sensing or controlling device that is attached to any other
pin on the TTL I/O connector. The Vcc pin should not be used to source current. The TTL I/O pins are defined as
follows:
Pin
1
Pin
9