Description
PLC的程序一般不能按事先设定的循环周期运行。PLC程序是从头到尾执行一次后又从头开始执行。（现在一些新型PLC有所改进，不过对任务周期的数量还是有限制）而DCS可以设定任务周期。比如，快速任务等。同样是传感器的采样，压力传感器的变化时间很短，我们可以用200ms的任务周期采样，而温度传感器的滞后时间很大，我们可以用2s的任务周期采样。这样，DCS可以合理的调度控制器的资源。
Juniper SA2000 SSL VPN Appliance IVE Platform
90 Day Warranty – Free US Shipping!
Nortel NT0H10CB ONS5200 OCI 1.25G 1310NM SMF/MMF IR
90 Day Hardware Warranty – Free Overnight Shipping!
Nortel OCM NT0H40BC Optical Channel Manager Optera 5200
90 Day Warranty – Free Overnight Shipping!
Nokia NIF4524FRU 4 Port 1000Base-T cPCI Mgmt FRU IP2255
90 Day Warranty – Free Worldwide Priority Shipping!
Nortel Arris Cornerstone D-Link CMTS Modem Mod NTBN19DA
90 Day Warranty – Free Shipping!
Nortel NT0H01JA OPTera Metro 5200 OCLD 1.25Gbps Band 5
90 Day Hardware Warranty – Free Overnight Shipping!
Nortel OPTera Metro 5200 OC48 Line card NT0H02BC ONS
Why Pay 11k for new? 30 day warranty!
Nortel DS1404005 Passport 8624FX Switch 100B FX MT RJ
Layer 3 switching – in stock – free shipping
Redback AIM-1K-2OC3SM VAC1DEOAAA SMS 1800 2 Port OC3 SM
90 Day Warranty – Free Shipping
